1. Field of the Invention:
This invention relates to circuit interrupters and more particularly to a current limiting circuit interrupter providing for triple break interruption.
2. Description of the Prior Art:
It is known in the prior art to provide a circuit interrupter having an elongated current carrying contact arm in which an overload current generates electromagnetic forces to cause a magnetic drive device or slot motor to drive the contact arm to an open position at high speed to provide current limiting action. An example of such a circuit interrupter is disclosed in U.S. Pat. No. 3,815,059 to L. A. Spoelman which discloses a circuit interrupter in series with an electromagnetic current limiting device which utilizes forces generated by the overload current to drive the movable contact arm open. In U.S. Pat. No. 3,815,059 the current limiting device is provided with a movable contact arm which pivots around one end and which moves into the slot of a magnetic drive device during circuit interruption. One advantage of a magnetic drive circuit interrupter in conjunction with a circuit breaker, such as a common toggle-type breaker, is that the current limiting device can be reset and reused after each operation without requiring replacement of fuses.
In the circuit interrupter art it has long been recognized that it is a distinct advantage to provide fast interruption of an established arc. As well known by those skilled in the art, it is desirable to effect a rapid extinction of the arc as quickly as possible inasmuch as the current flow through electrical equipment will damage the equipment unless the fault current is limited. Likewise, the ability to rapidly reset and reuse the current limiting device is desirable, that is resettable circuit interrupters have many well-recognized advantages over fused devices.